Fosi N3 Bluetooth Receiver/Amplifier Review

Citied from Joe Smith (location Iowa, US) 

Fosi Audio recently sent me a fairly new product to try out, their N3 bluetooth receiver/headphone amp. It's a bit of a niche product but I was interested to review one after seeing the photos. It is currently available on "that auction site" for $60, but I don't see it yet on Fosi's main website.

The device can be used in two ways: 1) to receive a BT signal and amplify it to a headphone, or 2) to receive a line in signal and amplify it to a headphone. While the box says it is a "DAC and headphone amplifier," I think it is in fact just a BT receiver/amplifier.

It's very compact - 3.5" x 2" x .5" - case is black anodized. Weight is 40 grams per Fosi's data. Battery life is about 10-12 hours, charging is via a USB-C port on the bottom of the unit using a normal 5v/1a phone charger (not supplied). Fit and finish is nice, with a few caveats noted below.

Sound quality using my normal earbuds or headphones is good. Volume control is via a rotary thumbwheel (see below). They do not list recommended impedances, but power would be OK for low to medium impedance products. There is switchable GAIN and BASS on the main control side of the unit. They both work well. There is not a large change from low to high gain. The bass boost is a nice amount. It reminded me of the nice bass jump ("1" boost) available on my old Fiio E7 Dac/Amp. This unit reminded me a bit of the old Fiio in appearance and it's just a tad smaller.

Pairing was easy with either my iPhone or a laptop. BT reception was good, I have an old 1900s house and it could not get through multiple plaster walls upstairs, but the line of sight transmission to 20-25 feet was good.

Packaging is basic, just the device, short manual and a USB-C charging cable. A foam insert in the box protects the device for shipment.

Other Pros:
1) Nice compact size.
2) Fosi picked up the ORANGE color from the recent V3 amp knob and uses that for the main POWER button on this unit. Nice pop of color.
3) Battery LEDS are easy to see and understand.
4) Nice fit and finish overall.
5) Setup is very easy.
6) It has sufficient power to work with normal low to mid impedance headphones/IEMs.

Cons:
1) There are NO volume markings on the volume thumbwheel or case. I've called this out to Fosi as something they should change next time around. It would be pretty easy to mis-remember the way the knob turns and blast your ears if not cautious when using the unit.
2) When no music is playing, I clearly hear a soft hum (like a "carrier frequency") from the BT signal with my headphones. It's not noticeable when music is playing, but it's enough to affect sound quality. Not present when using the AUX IN.
3) The plastic window with the Fosi logo serves no function whatsoever, it is just for show, and is very scratchable. I thought that was where I'd see something lit up or a volume level. Wrong! It's just a weird design thing and will scratch over time.
4) Screws on the back side detract a bit from appearance, but it would make it easier to open the case if need be - but for the price point, can't imagine repairs are going to occur, really.
5) Could really benefit from a rubber sleeve like my old Fiio DAC had to protect the finish and make it less likely to slip around on a table, or fall out of a shirt pocket.

I appreciate Fosi sending this to me and letting me test out. In general, I feel this is a pretty niche device, good to use if you specifically need to walk around with headphones and you are willing to use basic Bluetooth as the source.